The present invention relates to the field of image projection systems, and more particularly to displaying an image in response to the proximity of the observer.
In U.S. patent applications Ser. Nos. 09/519,537 and 09/876,400, an invention was disclosed whereby a substantially transparent medium could be used as a projection screen for capturing an image from an image projector. When the medium was not capturing an image from an image projector, its substantially transparent characteristic permitted persons to see through the medium. However, the system also provided an ability for the medium to capture an image from an image projector for viewing by persons. In one embodiment, the medium was made to have a characteristic that caused it to be nearly opaque, or substantially translucent (permitting the passage of light, but not sufficient as to be able to view objects clearly), so that persons could see clearly the image projected.
However, these image projection systems did not display an image in response to the proximity of the observer in order to capture the attention of a passerby, provide more information to the observer, etc.
Therefore, it would be desirable for an image projection system to display an image in response to the proximity of the observer.